Species extinction is 35 times faster since the appearance of humans

In a book about the future of artificial intelligence, MIT professor Max Tegmark proposes an absurd and frightening scenario: if we were not able to accurately convey our objectives, machines could adopt a goal of their own far removed from our interests, such as transforming all the atoms in the universe into metal clips. including those of our own bodies. Criticized for the extravagance of its end, the mechanical mind could be excused in that it was trained by observing its creators. In recent decades, human intelligence has achieved an unprecedented expansion of the species thanks to a use of ingenuity to, with a terrifying homogenizing efficiency, turn other living beings into food to support more humans and products to make their lives more pleasant. This species, whose ancestors had critical moments in which there were just over a thousand individuals, already accounts for 36% of all mammals that exist. Another 60% are animals such as cows, raised to feed people, and only 4% are wild animals.

Despite humanity's impact on terrestrial ecosystems, we only account for 0.01% of the planet's biomass. However, humans continue their advance, reducing space for other animals and becoming increasingly alone. This sixth mass extinction, after others produced by meteorites, such as the one that wiped out the dinosaurs, or extreme geological processes, is the first caused by a single animal. And the impact is not limited to isolated species. According to an article published today in the journal PNAS, entire branches of the tree of evolution are being mutilated. Animals such as the Tasmanian tiger or the Yangtze dolphin were the last of their genus, a concept that groups several related species.

More information

Seven of the nine thresholds that allow human life on Earth have already been surpassed.

The work, led by Gerardo Ceballos, a researcher at the National Autonomous University of Mexico, examined 34,600 species of 5,400 vertebrate genera during the last 500 years from databases such as the International Union for Conservation of Nature. In that time, 73 genera went extinct at a rate 35 times faster than would have been expected if they had followed the speed of the previous 65 million years. Without human influence, it would have taken 18,000 years to see so many genera disappear. According to the authors, at least one-third of known vertebrates are losing population and are being cornered in smaller and smaller ecosystems. At the beginning of the twentieth century there were 10 million elephants. Today there are less than half a million and they have disappeared from many of the countries they inhabited until recently.

The loss of an entire genus can have an impact on the functioning of an entire ecosystem. The homogenization imposed by humans on their environment is also making disappear a beneficial balance for our existence and changing the course of evolution. "In the eastern United States, large predators, bears, cougars, wolves, and white-tailed deer increased in a stratospheric way, and also mice. Deer and mice are hosts of ticks that transmit a very serious disease that is Lyme disease. That has meant that there are millions of cases per year in the United States, "exemplifies Gerardo Ceballos. In a less pragmatic tone, Paul Ehrlich, a professor at Stanford University and co-author of the study, says that "we are losing the only living companions we know of in the entire universe."

The loss of biodiversity and the overexploitation of wild space is facilitating the jump of diseases between animals and humans, as happened with covid, but it is also destroying resources that can serve to improve human health. One of the missing genera is the gastric incubator frogs (Rheobatrachus), which lived in the tropical forests of Queensland, Australia. These animals had a peculiar reproductive system. The females swallowed the fertilized eggs and turned their stomachs into wombs where tadpoles grew. Since frogs had to shut down acid secretion in their stomach to protect their young, they were an interesting research model for diseases such as gastric reflux and associated cancers, but there are none left on Earth anymore. Animals such as these, despite their small numbers, can also play an important role in maintaining ecological balances.

Ceballos states that his data is a call to action and that "if we do not act on the necessary scale, there will be a collapse of civilization. The human being is not going to become extinct, but there will be these situations of apocalyptic movies in which only the strongest survive, "he adds. In the past, after each major extinction, which has sometimes wiped out more than 70% of life on Earth, the tree of life was rebuilt with the slow emergence of new species. "But it took 15 or 20 million years and humanity can't wait that long," warns Ceballos.

To avoid or mitigate the collapse, the authors demand an unprecedented investment, with a special attention to the conservation of tropical forests, which are the places where the greatest biodiversity is found. "This would perhaps cost 400,000 million dollars, which is a significant amount, but if we continue as we have until now there will be a much more widespread collapse than we are seeing," warns Ceballos. Despite the degree of understanding of the problem that studies such as the one published today by PNAS offer on the dimension of the ecological challenge facing humanity, the only known intelligent species in the universe is getting closer to suffocating with its own efficiency to survive and reproduce.

You can follow MATERIA on Facebook, Twitter and Instagram, or sign up here to receive our weekly newsletter.